Egg carton



June 20, 1967 F. L. BURKETT EGG CARTON 2 Sheets-Sheet 1 Filed July 19,1965 INVENTOR. Franc/l5 L. Burke/:

6 770/? NE Y June 1967 F. L. BURKETT EGG CARTON 2 Sheets-Sheet 2 FiledJuly 19, 1965 INVENTOR. Franc/ls L. Burke 1)! fimm;

HTTOIQNEY United States Patent 3,326,443 EGG CARTON Francis L. Burkett,Breckenridge, Mich, assignor to The Dow Chemical Company, Midland,Mich., a corporation of Delaware Filed July 19, 1965, Ser. No. 473,027 9Claims. (Cl. 229-25) This invention relates generally to an egg cartonformed from foam plastic sheet material. More particularly, thisinvention relates to a vacuum, matched-die formed foam plastic cartonconstruction providing numerous improvements such as an especiallyhigh-shock -absorbing cell structure for eggs and a highly secure latchconstruction. In one embodiment, an egg carton includes the novel foamplastic base of this invention in combination with an improvedsee-through film cover.

Prior to the present invention, there was no carton providing completelysatisfactory cushioning of eggs contained in its cells such that theeggs, even under excessive conditions of load or impact, would remainunbroken. It is thus an object of the present invention to provide afoam plastic egg carton having substantially improved cushioningproperties over prior art cartons such as that shown by US. Patent No.3,093,286, for example.

Prior egg cartons have also failed to provide a secure, simple latchmechanism, especially when formed of a foam plastic material. It istherefore another object of the present invention to provide asubstantially improved latch mechanism for a foam plastic egg carton orthe like.

Still another object of the present invention is to provide anall-plastic egg carton construction having extremely superior cushioningproperties, structural strength to handle high-vertical loads, whileproviding free viewing of the contents.

Briefly then, the present invention comprises providing an all-foamplastic egg carton having improved cooperatively associated cushions inthe egg cell walls and the lid to achieve high resistance to load andimpact forces. The cushions are formed by opposed vacuum drawing of theheated foam plastic sheet forming the carton. The invention furthercomprises an all-foam plastic carton having a novel acute angle latcharrangement formed integrally therein to lock the carton shut in anespecially secure fashion. The aperture through which the locking memberprotrudes has a greatly strengthened bulbular ridge about its periphery.Also comprehended is an all-plastic egg carton construction having asee-through plastic top with a greatly cushioned foam plastic bottom,the combination providing a carton having high vertical load strength.

Yet additional objects and advantages of the present invention, and itsnumerous cognate benefits and features are even more apparent andmanifest in and by the ensuing description taken in conjunction with theac companying drawing in which wheresoever possible, like characters ofreference designate corresponding material and parts throughout theseveral views thereof, in which:

FIGURE 1 is a plan view of an open egg carton constducted according tothe principles of the present invention;

FIGURE 2 is a front-elevational view thereof, with a portion brokenaway;

FIGURE 3 is a greatly enlarged cross-sectional view thereof taken alongreference line 3'3 of FIG. 1;

FIGURE 4 is a greatly enlarged fragmentary crosssectional view thereoftaken along reference line 4-4 of FIG. 1;

FIGURE 5 is an enlarged fragmentary cross-sectional view thereof takenalong reference lines 5-5 of FIG. 2;

FIGURE 6 is an enlarged fragmentary view of FIG. 1 showing a step in themaking of a portion thereof;

FIGURE 7 is a plan view of a modified form of egg carton with a portionthereof broken away;

FIGURE 8 is an elevational view thereof with portions broken away; and

FIGURE 9 is an enlarged fragmentary cross-sectional view taken along thereference line 9-9 of FIG. 7.

Referring more particularly to FIGS. 1 to 4, there is shoWn athermoplastic egg carton 10, which carton can be formed from a one-piecesheet material such as eX- panded polystyrene. The carton 10 basicallycomprises a tray portion or base 22, cover or lid 24 and front flap 26,the lid and flap preferably hingedly connected to opposite sides of base22. The generally elongated rectangular base 22, as illustrated, has onedozen egg cells 12.

The carton 10 is basically formed into shape from the sheet materialgenerally by plug assist vacuum drawing. Egg cells 12 are particularlyformed by a matching die technique with the plug grooved and fitted forvacuum operation so that a plurality of side ribs or cushions 14 andbottom puffed cushion pad 16 are formed, by opposed vacuum drawing, onthe inside of the cell wall of each cell 12. Similar opposed vacuumforming on opposite sides of the lid structure forms expanded cushionsor pads 13 generally opposed to pads 16.

These cushions 14, 16 and 18 cradle the egg 20 as shown in FIG. 2 andsubstantially prevent movement of the egg during transporting of thecarton. For severe impact and load stacking stresses the uniquecushioning effect of the cushions 14, 16 and 18 aids substantially inprevention of rupture of the egg wall. It is believed this much improvedcushioning is achieved because of the lower density of the cushions 14,16 and 18, the walls of the cellular structure of the foam itself beingthinner than the rest of the carton permitting more ready flexingthereof during stress applications. These conditions ap parently areachieved because of the opposed vacuum drawing technique employed informing the cushions 14, 16 and 18.

By being puffed up, the cushions, particularly opposed cushions 16 and18, also provide flexibility in cradling eggs of different sizes andshapes. Larger eggs will fit snugly into opposed cushions 16 and 18while smaller eggs can still be secured between these cushions with thelatter being in a less compressed state. Likewise, of course, sidecushions 14 provide flexibility in cradling eggs of Wide or narrowconfigurations. The exact number and shape of pads 14 may be varied fromthat shown and still be within the scope of the invention.

Latch projections 28 protrude outwardly from flap 26 at an angle a whichis acute to the flat outer surface 30 of flap 26 (shown most clearly inFIG. 5). Since front wall 34 of lid 24 is substantially parallel withsurface 30, projection 28 will also be at an acute angle with the frontwall 34. In this particular illustration angle a is about 71, it beingunderstood that this angle can vary several degrees in either directionand still accomplish the object of the present invention.

Adapted to mate with each projection 28 is an aperture 32 along thefront wall 34 of lid 24. The aperture 32 includes about its peripheraledge a bulbular ridge 36 providing an aperture highly resistant totearing at its edges. This ridge 36 is formed by squeezing the foamplastic material while in a heated condition so as to extrude a bulbularmass from under a forming tool 40, this bulbular mass forming peripheralridge 36. FIG. 6 illustrates this ridge forming step, with it beingunderstood that aperture 32 is not fully formed at this stage but mustbe later cut out in a customary manner by a cutting tool (not shown).Ridge 36 is formed using only material which otherwise would have beenwasted.

Thus, when a projection 28 extends through aperture 32 it is securelylocked about peripheral ridge '36. That is, the undercut provided by theangle a on the under side of latch projection 28 insures a more positivesealing action with the aperture 32, especially where a ridge 36 isemployed.

Modified carton 42, illustrated in FIGS. 7 to 9, comprises a foamplastic tray-like base 44 and a film cover 46, which cover may be fittedto the foam bottom. Preferably, base 44 is formed in the manner asdescribed earlier with respect to base 22 of carton 10. Thus base 44includes a dozen egg cells 48 with each cell having side cushion pads 50and a bottom cushion pad 52 which are similar to cushions 14 and 16previously described.

Cover 46 is preferably formed of a clear or transparent or translucentpolystyrene or other comparable plastic film or sheet material capableof maintaining its weight and shape generally without additionalsupport. Cover 46 can be pressure formed to achieve the shapeillustrated, which forming technique is well known in the art. Base 44includes pillars 50 which extend above the rim 52 of the base to aheight which will support the flap top portion 54 of cover 46. By havingsuch a high pillar structure the strength of the cover 46 is greatlyincreased, particularly for stacking purposes. A horizontally disposedshoulder 56, formed integral with base 44 and its rim 52, is in matingdisposition with a similarly disposed shoulder 58 of cover 46, themutual support of the shoulders 56 and 58 further strengthening thestacking ability of carton 42. Thus, there is shown a novel carton whichachieves improved egg cushioning while permitting visual inspection ofthe eggs when the carton is in a closed position.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications can be madetherein without departing from the spirit and scope of the invention.Such changes can be in other structures and materials which serve toachieve the principles of this invention.

Accordingly, what is claimed as new is:

1. An egg carton having a tray-like base, a lid covering the top of saidbase, said base comprising foam plastic material, a plurality of eggcells integral with said base, cushions being integrally formed with thecell walls and extending interiorly about the walls of each of saidcells adapted to cradle an egg, said cushions having a density less thanthat of the rest of the carton.

2. The cart-on of claim 1 wherein the foam material comprising saidcushions has a thinner cellular structure than that of the rest of thecarton.

3. The carton of claim 2 wherein said cushions are about the side andbottom walls of each said cell.

4. The carton of claim 3 wherein said lid comprises a transparentplastic film material.

5. The carton of claim 4 wherein pillars extend from said base to thetop of said lid.

6. An egg carton having a tray-like base, a lid covering the top of saidbase, said base and lid comprising foam plastic material, a plurality ofegg cells formed in said base, cushions being integrally formed with thecell walls and extending interiorly about the walls of each of saidcells, at least one of said cushions being centrally located about thecenter of the bottom wall of each said cell, a cushion located in saidlid in a position opposite from the bottom wall cushions of each eggcell whereby said opposing cushions cradle an egg in each cell.

7. The carton of claim 6 wherein additional ones of said cushions extendinwardly from the side wall of each said egg cell.

8. The carton of claim 7 wherein each of said cushions has a density andcellular structure less than that of the rest of the carton.

9. A foam plastic egg carton having a tray-like base, a lid covering thetop of said base and including a front wall portion, a front flap, saidbase hingedly connected with said lid and flap on opposite sidesthereof, the flap extending upwardly from said base behind and generallyparallel with front wall portion of said lid when the carton is in aclosed position, at least one latch projection extending outwardly fromthe front surface of said flap and downwardly at an acute angletherewith to define a wedge-shaped undercut, said front wall portioninclud ing an aperture mating with said latch projection, a bulbularridge formed at least along the bottom peripheral edge of said aperture,said latch projection extending through the aperture such that an edgeof the aperture fits within said undercut.

References Cited UNITED STATES PATENTS 2,737,503 3/1956 Sprague et al.

2,971,685 2/ 196 1 Treida 22929 X 2,979,246 4/1961 Liebeskind 229--143,093,286 6/1963 Brickner et al. 229-2.5 3,129,866 4/1964 Wade 22929 X3,176,899 4/1965 McMahon 22929 3,191,791 6/1965 Jackson 2292.5 X3,207,409 9/1965 Reifers et al. 22925 GEORGE O. RALSTON, PrimaryExaminer.

1. AN EGG CARTON HAVING A TRAY-LIKE BASE, A LID COVERING THE TOP OF SAIDBASE, SAID BASE COMPRISING FOAM PLASTIC MATERIAL, A PLURALITY OF EGGCELLS INTEGRAL WITH SAID BASE, CUSHIONS BEING INTEGRALLY FORMED WITH THECELL WALLS AND EXTENDING INTERIORLY ABOUT THE WALLS OF EACH OF SAIDCELLS